1. Field of the Invention
The invention relates to a mounting structure for an electric appliance mounted in a vehicle and, more particularly, to a vehicular battery mounting structure in which a battery pack is mounted on a floor panel of a vehicle.
2. Description of the Related Art
In order to achieve improved fuel economy and clean exhaust gas, the development of vehicles having new driving mechanisms, such as electric vehicles, hybrid vehicles, etc., has been pursued. Such vehicles need to be equipped with electric appliances that are not provided in the vehicles that have an internal combustion engine as a sole vehicle driving power source. Examples of such electric appliances include a traction motor of an electric vehicle or a hybrid vehicle, a secondary battery that supplies power to a starter to restart an engine in conjunction with an idling stop system for stopping the engine at the time of an idling condition, etc. The mounting position of such an electric appliance needs to be determined in view of effective utilization of the cabin space and the trunk space of the vehicle, safety securement at the time of a collision accident, etc.
Japanese Patent Application Laid-Open Publication No. 2000-233648 discloses a vehicle in which a battery is mounted on a floor panel in a cabin. The vehicle disclosed therein is a vehicle in which a battery (battery pack) is mounted above the floor panel and, more specifically, the battery is disposed within a space surrounded by a closed-section member that is disposed on the floor panel. This battery has a cooling structure in which an air introduction means for introducing air is connected to the closed-section member, and an air outlet is formed at a location in the closed-section member which corresponds to the battery. Furthermore, this battery is divided into a driver seat-side section and a passenger seat-side section which are mounted below the driver seat and the passenger seat, respectively.
According to the above-described battery mounting structure, the closed-section member provided on the floor panel can be effectively used as a ventilating and cooling duct. Therefore, the structure does not need new provision of a duct or the like, and allows the ventilation and cooling of the battery disposed in the cabin without degrading the ease of layout in the cabin.
However, the foregoing battery mounting structure has problems as stated below. That is, a battery (battery pack) mounted has a structure that is formed by stacking a plurality of battery cells in the direction of a width of the vehicle. Cooling passageways are provided between battery cells, and conduct cooling air from top to bottom or from bottom to top. In order to uniformly introduce cooling air into the cooling passages, a chamber is needed. The chamber is provided above or below the battery cells. Therefore, the height of the battery pack is becomes great. However, the under-seat space has severe restrictions on the dimension in the vertical direction. Therefore, the containment of a battery within the under-seat space is not easy. Furthermore, since the inlet and outlet ducts for the battery are formed by using a vehicle body member, the structure becomes complicated.